Production of chloride-free potassium phosphates

ABSTRACT

A PROCESS FOR THE PRODUCTION OF CHLORINE, HYDROGEN, AND HIGH ANALYSIS CHLORIDE-FREE POTASSIUM ORTHOPHOSPHATE AND POTASSIUM POLYPHOSPHATE FERTILIZERS. SATURATED POTASSIUM CHLORIDE BRINE AND MERCURY ARE PUMPED INTO A MERCURY CELL WHERE THE BRINE IS ELECTROLYZED TO PRODUCE CHLORINE AT THE ANODE AND POTASSIUM AMALGAM AT THE MERCURY CATHODE. WATER AND EITHER ORTHOPHOSPHORIC OR POLYPHOSPHORIC ACID SOLUTION ARE FED TO THE DECOMPOSER UNIT WHERE THE AMALGAM IS SUBSEQUENTLY STRIPPED OF POTASSIUM IN THE PRODUCTION OF HYDROGEN GAS AND POTASSIUM PHOSPHATE SOLUTION, SOLIDS, OR SOLUTION WITH SOLIDS. DECOMPOSITION IS EFFECTED WITH OR WITHOUT SHORT-CURCUITING ELEMENTS, IN THE DECOMPOSER. THE SPENT BRINE IS RESATURATED WITH SOLID POTASSIUM CHLORIDE. THE RESATURATED BRINE AND THE MERCURY RECOVERED FROM THE DECOMPOSED AMALGAM ARE RECYCLED TO THE ELECTROLYSIS CELL. STABLE POTASSIUMPOLYPHOSPHATE SOLUTIONS AS CONCENTRATED AS 70 PERCENT IN PLANT FOOD   (P2O5%+K2O%)   ARE PROPOSED; A CONCENTRATION OF 62 PERCENT PLANT FOOD WAS ATTAINED IN A STABLE POTASSIUM POLYPHOSPHATE SOLUTION WITH A PH OF 7.67 AND A DENSITY OF 1.740 G/ML. AT 25*C.

DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 0.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Oflice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED SEPTEMBER 11, 1973 SATURATE BRINE a 1 I-enos rat ome mx TANK 4 PUMP SOLUTION AND SOLID PRODUCT FILTER SOLID PRODm REQCLE OLUTION KCOWOSER "UNION PROIJUGY A process for the production of chlorine, hydrogen, and high analysis chloride-free potassium orthophosphate and potassium polyphosphate fertilizers. Saturated potassium chloride brine and mercury are pumped into a mercury cell where the brine is electrolyzed to produce chlorine at the anode and potassium amalgam at the mercury cathode. Water and either orthophosphoric or polyphosphoric acid solution are fed to the decomposer unit where the amalgam is subsequently stripped of potassium in the production of hydrogen gas and potassium phosphate solution, solids, or solution with solids. Decomposition is effected with or without slront-circuiting elements in the decomposer. The spent brine is resaturated with solid potassium chloride. The resaturated brine and the mercury recovered from the decomposed amalgam are recycled to the electrolysis cell. Stable potassium polyphosphate solutions as concentrated as 70 percent in plant food are proposed; a concentration of 62 percent plant food was attained in a stable potassium polyphosphate solution with a pH of 7.67 and a density of 1.740 g./ml. at 25 C.

SepLll, 1973 v T. P. HIGNETT T T914907 PRODUCTION OF CHLORIDE-FREE POTASSIUM PHOSPHATES Filed Oct. 10, 1972 I 5 Sheets-Sheet 2 PHOlSXETIDORIO PRODUCT PUMPS 2 SOLUTION 4,4 T'A'AK f? a i6 MAGNETIC STIRRER AND HEATER p 1973 T. P. HIGNETT ETAL PRODUCTION OF CHLORIDE-FREE POTASSIUM PHOSPHATES 5 Sheets-Sheet 3 Filed Oct. 10, 1972 KOH HCI SURGE TANK PRODUCT G V PUMP MAGNETIC STIRRER Se pLl l, 1973 T. P. HIGNETT ETAL T9l4,007

PRODUCTION OF CHLORIDE-FREE POTASSIUM PHOSPHATES Filed Oct. 10, 1972 s Sheets-Shoat. 1

SPENT KCI h l BRINE SATURATOR U I SURGE TANK PUMP l r i QUALITY CONTROL ll 1 2 PHOSPHATES Sept.l1, 1973 T. P. HIGNETT ETAL T9l4,007

PRODUCTION OF' CHLORIDITFREE POTASSIUM PHOSPHATES Filed Oct. 10, 1972 5 Sheets-Sheei 5 I" 2 THERMOCOUPLE H PO HOT WAT ER W HOT SURG E PROCESS TANK HOT WATER PHOSPHATES MAGNETIC ST IRR ER AND HOT PLATE 

